Desiccation of molten metal chlorides



atent Nov. 22, 19 27.

STATES PATENT OFFICE.

WILHELM MOSCHEL AND P I-IILIPP SIEDLER, OF GBIESHEIM-ON-THE-MAIN, GER- MANY, ASSIGNORS TO THE FIRM I. G. FARBENINDUSTRIE AKTIENGESELLSCHAIT, 01F FRANKFORT-ON THE-MAIN, GERMANY.

DESIGCATION OI MOLTEN METAL GHLORID'ES.

This invention relates to'the desiccating" of certain salts containing water of crystallization, as alkaline earth metal chlorides (for instance calcium chloride 0e01,), magnesium chloride MgCl or double salts of these, as for instance carnallite KMgCl -6H O which salts in the molten state are used as electrolytes to obtain metals therefrom. It is well known that the last traces of water can be removed from salts of this kind onl with difliculty. If salts containing a sma 1 amount of water are used for forming the molten bath, basic salts, such as MgCl-OH will be formed, which incessantly develop hydrogen chloride and produce a continuous separation of oxides. These oxides are, owing to their manner of formation, so finely distributed in the molten bath that the mud of oxides is not deposited even in the stagnant bath. If the muddy. electrolyte is employed for electrolysis it is gradually entirely desiccated, it is true, but.

this is effected by the metal, first separated, acting on the basic salts so that this desiccation takes place at the expense of the current output.

Now we have found that. the desiccation cium carbide.

Drawing. Application filed February 11, 1926, Serial No. 87,714, and in Germany February 16,1925.

and, at the same time, the removal of the mud can be rapidly and thoroughly performed by treating the previously molten raw salt with calcium carbide CaC When calcium carbide in a granulated form is introduced into the molten bath being in a certain excess over the amount of water present therein, a strong development of acetylene (1 H, results; whereas the caustic lime that is formed is deposited subs'tantially upon the grains of the carbide. Owing to its relatively coarse distribution the mud of oxides is deposited so fast that after a short time the wholly desiccated mass may be poured off. A bath obtained in this manner yields from the first an output of metal which is only just influenced by the solubility of chlorine in the molten bath. We claim A method of producing anhydrous chlorides which comprises treating a molten hydrated metal chloride with granulated cal- 50 In testimony whereof we aflix our signatures.

' WILHELM MOSOHEL.

PHILIPP SIEDLER. 

